Sawmill log indexing device

ABSTRACT

An indexing mechanism for use in a log sawmill which is mounted on the log carriage remote from the log mounting chucks. The indexing device enables the operator to position the log accurately for cutting and to rotate the log for subsequent cuts. The device is remote from the mounting chucks so that it can be protected from mechanical damage and so that it can be dimensioned to provide extremely accurate indexing.

United States Patent [191 Mackin Jan. 22, 1974 SAWMILL LOG INDEXINGDEVICE [75] Inventor: Wilson Joseph Mackin, Vancouver,

B.C., Canada [73] Assignee: Greenleaf Holdings Limited,

Vancouver, British Columbia, Canada [22] Filed: June 28, 1972 [21] App].No.: 267,209

Related US. Application Data [63] Continuation of Ser. No. 6,349, Jan.28, 1970,

abandoned.

[30] Foreign Application Priority Data Jan. 29, 1969 Canada 41441 [52]US. Cl 83/708, 83/712, 269/5433, 83/4253, 83/4351 [51] Int. Cl B271)7/04, B27b 29/08 [58] Field of Search 83/708, 712, 425.3, 425.4,83/4044, 435.1; 269/5413 [56] References Cited UNITED STATES PATENTS2,673,581 3/1954 Domath et a1 83/708 2,803,272 8/1957 Crosby 83/4044Primary ExaminerDona1d R. Schran Attorney, Agent, or Firm-Stevens,Davis, Miller &

Mosher [5 7] ABSTRACT An indexing mechanism for use in a log sawmillwhich is mounted on the log carriage remote from the log mountingchucks. The indexing device enables the op? erator to position the logaccurately for cutting and to rotate the log for subsequent cuts. Thedevice is remote from the mounting chucks so that it can be protectedfrom mechanical damage and so that it can be 7 dimensioned to provideextremely accurate indexing.

7 Claims, 5 Drawing Figures PATENTEDJMZZ 1974 4 3786712 SHEET 2 m5 FIG.2

SHEEI BF 5 SAWMHJ. LOG INDEXING DEVICE This is a continuation, ofapplication Ser. No. 6,349, filed Jan. 28, 1970 now abandoned.

This invention relates to an improved sawmill and more particularly toan improved log indexing mechanism.

Sawmills employing a sliding carriage having adjustable holding meanswhereby logs of various diameters may be inserted and moved with thecarriage through a sawing unit are well known to the art.

Raw timber is seldom, if ever, uniform in structure and if a single sawcut is made there is a marked tendency for the stock to twist or bend asthe internal compressional or tensional forces are released; thisphenomena is known as Timber bind which is much more prevalent inhardwood species. The sawing unit is, therefore, normally a double sawunit to minimize Timber bind, or bowing of the wood on one side. The sawblades are laterally spaced and vertical and may be fixed relative toeach other or adjustable. It is also known to provide chucking meanswhereby a log may be centered longitudinally in the chucks and held inplace by application of pressure on the chucks for movement through thesaw unit, as opposed to laying a log on a carriage bed for sawing.

Dornath et al in US. Pat. No. 2,673,581 issued Mar. 30, 1954, describesuch a chucking means which is adapted to be indexed at predeterminedangles so that the bark may be removed from an entire log without thenecessity of releasing the chucks between successive saw cuts so thatthe log may be turned. This indexing system comprises a pair oflongitudinally disposed chucks each adapted to rotate in its respectivesupport member which in turn forms part of a sliding carriage, means toapply pressure to one of the chucks whereby the distance between thechucks can be altered to accommodate various length logs and hold themsecurely, a circular template having a plurality of radial slotsdisposed at 45 intervals around the circumference attached to the outerend of the chuck which does not include the pressure means, and amanually operated dog, attached to the chuck support for engaging in aselected radial slot to retain the chucks in a selected position. Aspreviously indicated, the sawing operation causes considerable Timberbind despite efforts to keep the effect to a minimum. The timber bindresults in a considerable torque being applied to the chucks and thus tothe indexing template and locking dog. Consequently these componentsmust, of necessity, be made in relatively massive proportions and as apractical matter the indexing template cannot be less than about 8inches diameter. As the entire template assembly must pass between thesaw blades, it is obvious that the Dornath et al. device can only beused on large timher and the discard or cant is no smaller than about 8inches in diameter. Because of the massive nature of the template andthe torque, which results in considerable wear in the slots and on thedog, the indexing can only be relatively coarse or inaccurate and cannotbe adapted to position a log to make the most advantageous use of thetimber. All logs contain irregularities such as knots and splits but bycareful attention to the cutting angles, many of the blemishes can beeliminated or minimised. Further, the accuracy and life of the Dornathindexer is reduced due to its location at the chuck where it rapidlybecomes covered with sawmill debris,

sawdust and the like. The probability of accidental damage is very high.

It is, therefore, an object of the present invention to provide animproved indexing means for a sawmill which overcomes the above-noteddisadvantages of the prior art.

Other objects and advantages will become apparent in the followingdetailed description of the invention particularly when taken inconjunction with the accompanying drawings which are illustrative, butnot limiting, of the present invention and in which:

FIG. 1 is a vertical sectional view of an indexer according to the priorart.

FIG. 2 is a vertical sectional view of an indexer according to thepresent invention; and

FIG. 3 is a vertical sectional view taken on the plane of section 33 ofFIG. 2 and includes a view of the saw blades.

FIG. 4 is a vertical sectional view, similar to FIG. 3, of analternative embodiment.

FIG. 5 is a vertical sectional view of a further alternative embodiment.

Turning first to FIG. 1, there is shown an indexer according to theprior art. A log 1 is centered and held in compression by horizontallyopposed chucks. The pressure applying means and its associated chuck arenot shown. The illustrated chuck 2 is mounted on a shaft 3 passingthrough a vertical support 4 which includes a rack 5 and pinion 6 loglifting mechanism. The outer end of shaft 3 is provided with a circularindexing template 7 having 45 spaced circumferential slots into which adog 8, pivotally connected by a pin 9 to support 4, may be selectivelyinserted.

In the present invention, referring to FIGS. 2 and 3 a log 1 is centeredand held in chucks 11, only one of which is shown, in a similar mannerto the prior art. The chuck 11 is free to rotate in sleeve 12 mounted insupport 13. The support 13 is part of the complete log carriage 14 whichtransports the log past the saw blades 15 in conventional manner. Thecarriage 14 is normally suspended above the saw blades 15 on a pair oftrack beams 16 and 17. The carriage is provided with an upper transverseshaft 18 and associated trunnion wheels 19 and 20 which run on tracks 16and 17 respectively. A lower transverse shaft 21 is provided with wheels22 and 23 which run in contact with the undersides of tracks 16 and 17to provide vertical stability for the carriage. Wheel 19 is grooved toaccommodate a flange on track 16 to provide lateral stability. It willbe appreciated that a similar wheel system is provided at the other endof the carriage (not shown).

In contrast to the prior art, a horizontal shaft 24 is rotatably mountedon carriage l4 remote from chuck 11 in support 25 and end plate 26, and,at the outer end 27 thereof, an indexing template 28 is attached. Thistemplate may take several forms depending on the accuracy or degree ofrotation required. In the embodiment shown in FIGS. 2 and 3, thecircular template 28 has radial slots spaced at angles around thecircumference. The slots may be straight sided but are preferablytapered, in order to minimize the effect of wear and retain accuracy. Asprocket 29 is axially and rigidly mounted on upper shaft 24intermediate support 25 and face plate 26. A horizontal lowerintermediate shaft 30 is rotatably mounted between support 31 and endplate 26 and provided with an axially and rigidly mounted sprocket 32,in vertical alignment with sprocket 29. Sprockets 29 and 32 areinterconnected by a chain or similar belt 33. Also mounted on shaft 30,intermediate support 31 and sprocket 32, there is a toothed pulley orthe like 34. This pulley 34 is connected to a similar pulley 35 at theouter end 36 of the shaft 37 of chuck 11, by means ofa tooth belt 38.Thus as template 28 is rotated the motion is transmitted to chuck 11 andthe log 1 is rotated. The number of teeth on sprockets 29 and 32 andpulleys 34 and 35 may, of course, be varied independently, as may theirdiameters so that any desired gearing ratio is achieved. By suitableselection of gearing the degree of rotation of log 1 may be controlledvery accurately. It will, of course, be appreciated that a preferredembodiment of the transmission system has been described and numerousmodifications are possible. For example, in certain circumstances shaft30 could be omitted and sprocket 32 mounted directly on end 36 of shaft37, however, this would entail a much larger pulley 35 which woulddetract from the ability of the equipment to handle small sizes oflumber.

Also mounted on the end plate 26, is a template locking means 39 whichmay be of several designs. In the embodiment shown in FIGS. 2 and 3locking means 39 comprises a hydraulic cylinder 40 which actuates alocking pin 41, shown withdrawn in FIG. 2, which engages in a selectedslot in template 28, as shown in FIG. 3. The pin 41 may be tapered orstraight depending upon the degree of accuracy required. Alternatively,the locking means 39 may be a solenoid switch, a pneumatic cylinder or amanually operated lever.

Mounted on the carriage side plate 42, an automatic means 43 to rotatetemplate 28 may be provided. In the embodiment shown in FIGS. 2 and 3,this means comprises a hydraulic cylinder 44 and a piston 45,operatively connected by a connecting bar 46 to the chain belt 33. Theextent of the rotation possible is merely a function of the stroke ofthe cylinder 44, pitch diameter of the sprockets and centre distance ofthe sprockets. By suitable arrangement, rotation in excess of 180 ispossible. It will be appreciated that the automatic means 43 is anoptional feature as manual rotation may be employed, and also that theautomatic means may take several forms as by a pneumatic cylinder,electric motor drive or solenoid valve.

In operation, a sawmill including the present invention as hereinbeforedescribed employs the following sequence of steps; a selected hardwoodor softwood log 1 which may vary in diameter from about 4 inches toabout 30 inches and vary in length from about 8 feet to about 14 feet ormore is lifted by a conventioal hoisting means into position betweenchucks l1, centered in known manner and then gripped by the chucks withapplied pressure. Locking means 39 is actuated to disengage pin 41 (FIG.2), and rotating means 43 is activated to rotate the log 1 to the mostadvantageous position for sawing so that the maximum yield is obtainedand defects in the sawn lumber reduced to a minimum. Locking means 39 isthen actuated in the reverse direction to extend pin 41 into engagementwith template 28 (FIG. 3) thereby fixing the position of the log 1 withrespect to the saw blades 15. The circular saw blades 15 are rotated,and the carriage 14 is then advanced along tracks 16 and 17 so that thelog 1 comes into sawing contact with the blades 15. When the sawingoperation is completed along the length of the log, the carriage motionis reversed and the carriage is returned to its starting position.Locking means 39 is then actuated to withdraw pin 41, rotating means 43is actuated so that piston 45 continues its stroke, thereby rotating theindexing template and, in turn, the log by the desired amount. When thelog has been turned through a predetermined angle which may be betweenabout 15 and although these angles are not critical, the rotating means43 is stopped and the locking pin 41 is reinserted. The next passthrough the saws is then commenced.

It will be appreciated that the remote indexing system may be completelyenclosed to prevent ingress of dust and saw debris, if desired. Theactual template employed can vary depending on the degree of accuracyrequired, although it has been found that in practice, indexing at 15angles is sufficiently precise for most operations. The system isentirely flexible and offers the advantage that the log may be rotatedto the most advantageous position for cutting before any indexing iscommenced as will be described in more detail hereinafter. Furthermore,it is a simple matter to change the template 28 if different angles arerequired, which is not possible with the indexing systems of the priorart. In the prior art the template bears the entire torque load of thechucks and in view of the relatively massive dimensions required, thenumber of slots is limited to a maximum of eight evenly spaced aroundthe periphery.

In the embodiment shown in FIG. 4, the template 28 and locking means 39are entirely superceded by a quadrant and dry reed switch system whichpermits infinite variable indexing and automation of the entire unit. Aquadrant 47 is rigidly mounted on the frame 26 at the position of theintermediate shaft 30, carrying any desired number of dry reed switches48. If the number of switches 48 is increased sufficiently substantiallyinfinite variable indexing may be effected. Switches 48 are mounted onthe arc of the quadrant 47 to coincide with the travel described by thesensing tip of a pointer 49, and preferably the switches 48 areinterconnected in pairs 90 apart, for reasons to be explainedhereinafter. In a manner well known in the electrical art, a selectedswitch 48 may be activated and the pointer automatically rotated in thedirection required to line up with that switch. Movement of the pointeroccurs as a result of hydraulic fluid being directed under pressure tothe appropriate end of the cylinder thus causing rod 45 and link 46 tomove linearly in the appropriate direction. The pointer 49, shaft 30 andsprockets 29 and 36 are thus rotated to the desired position by themovement of belts 33 and 38. When pointer 49 exactly coincides with thedesired reed switch 48 the solenoid hydraulic control valve in thehydraulic system closes and all movement is stopped in the desiredselected position. The hydraulic system is locked in neutral. Preferablya hydraulic locking valve (not shown) is installed in the hydrauliccircuit to prevent creep or movement in the cylinder 44 and thusmaintain positive indexing.

In operation a sawmill employing the embodiment of FIG. 4 may beoperated as follows: a log 1 is loaded into a loading cradle, centredand clamped between the chucks in known manner. The cradle arms are thenlowered to enable the log to be rotated. The sawyer operator thenmanually overrides the solenoid control valve in the hydraulic system sothat the log may be rotated through about 200, allowing for someoverlap, for visual inspection and an accurate determination of the mostadvantageous sawing position for grade recovery of the resulting lumber.When the selected position is reached the operator activates theautomatic system by activating an appropriate reed switch. The'controlsystem pointer 49 is moved by rotation of shaft 30 driven by thehydraulic system until the pointer accurately coincides with the switch48 and the hydraulic system locks in place. The saw carriage is thenactivated and the log 1 moves through the saws, and is returnedpreparatory to a second sawing operation. If it is desired to turn thelog through 90 for the second cut, which is the usual and preferredprocedure, the operator merely activates a turn control switch whichautomatically deactivates the first reed switch and activates the secondreed switch 48 which is interconnected with the previously activatedreed switch. As previously indicated the reed switches areinterconnected in pairs 90 apart so that rotation between this angle maybe automatically accomplished. When the second reed switch is activatedthe pointer is rotated to this second switch and deenergizes theappropriate solenoid control valve in the hydraulic system stoppingmovement of rod 45 and link 46. The log is turned as before and isautomatically locked in position for the second cut. It will, of course,be appreciated that the reed switches may be interconnected in pairs atany desired angle not necessarily at 90. If it is desired to change thesawing plane by an angle not included in the automatic interconnection,the sawyer manually overrides the solenoid control valve, as in thepreliminary set up of the log, selects the desired position and thenresets the automatic locking system. Thus complete flexibility andcontrol of indexing may be achieved. For safety and convenience, it ispreferred to include limit switches in the system so that the turningand indexing steps may only be effected when the saw carriage is in thecradle loading position. This precaution precludes the possibility ofaccidental rotation during the sawing movement.

The further embodiment shown in FIG. 5 is a further refinement of theembodiment shown in FIG. 4. In FIG. 5, the upper shaft 27 and itsassociated belt 33 have been eliminated and the hydraulic cylinder 44 isoperative-1y connected via piston 45 and a clamping means 50 sliding ina guide 51 to the drive belt 38. This reduces the total height of theindexing mechanism and simplifies the operating mechanism (forconvenience shaft 21 and trunnions 22 and 23 have been omitted from FIG.5). In operation, the embodiment in FIG. 5 is similar to that in FIG. 4.The log is centered and rotated to obtain the most advantageous sawingposition. Pointer 49 moves to active switch 48 and activates theautomatic hydraulic system 43 whereby piston 44 causes movement up ordown of piston 45 which is attached to clamping means 50. Clamping means50 slides up or down in guide 51, and causes rotation of belt 38. Afterthe first cut the other switch 48 is activated and rotation is effectedas in the embodiment of FIG. 4.

The minimum size of log which can be retained or handled by the indexerof the prior art is limited to about 8 inches diameter as the entiretemplate must pass between the saw blades, whereas the present inventionpermits logs of 4-5 inches diameter to be retained or handled, as onlythe chucks have to pass between the saw blades. The size of the chucksemployed is solely dependent on the weight of the logs to be handled,and bears no critical relation to the diameter of the logs. Clearly,hardwoods are heavier than softwoods per unit volume and may requireheavier chucking arrangements to accommodate them. The present inventionis particularly suitable for use in a hardwood sawmill although it may,of course, be employed to advantage in the processing of softwoodlumber. It will also be appreciated that the indexing means is small,relatively cheap and easy to install on any size of sawmill. It may beemployed on large permanent mills and also on light portable mills.

I claim:

1. Apparatus suitable for carrying a log through a pair of adjustablesaw blades which cut said log longitudinally into lumber, the apparatuscomprising; "aeairiag mafi'afiiaiait of whe elsadapted to ride along atleast one rail, the carriage being reciprocally movable to convey saidlog through said saw blades;

support means connected to the carriage;

a pair of chucks rotatably mounted in the support means and operable tosupport said log by engagement substantially centrally of each endthereof, one of the chucks being secured to one end of a chuck shaftthat can be driven to rotate the chuck and the log;

positioning means operatively coupled to said one end of the chuck shaftso that the log can be rotated, while chucked, to an initial selectedindex position that allows the maximum lumber recovery from the logbeing sawed, the positioning means including a shaft rotatably mountedin the support means remote from said chuck shaft, and having a freeouter end thereof, further including nonextensible chain drive means forcoupling said shafts together, said chain drive means being adaptedto bedriven to rotate the chuck and the indexing means secured to the freeend of one of the shafts, the indexing means having a plurality of indexpositions thereon in co-ordinated pairs spaced apart to enable rotationof 90 from the 2. The apparatus of claim 1, wherein the indexing meanscomprises a circular template having said index positions thereondefined by a series of radially disposed slots on the periphery thereof,and wherein said locking means includes a reciprocally movable pin meansof a shape complemental to said slots, the pin means being engageable inthe slots to positively lock said positioning means in position.

3. The apparatus of claim 1, wherein automatically actuatable drivemeans are operatively coupled to said chain drive means, theautomatically actuatable drive means being responsive to a signalprovided by a sawyer to effect movement of the chain drive means andsimultaneously therewith rotation of the log carried by the two chucks.

4. The apparatus of claim 1, wherein said chain drive means isoperatively coupled to a piston and cylinder combination, saidcombination being actuatable to cause reciprocal movement of the pistonwith such movement simultaneously effecting rotational movement of saidchuck shaft and the log being carried by the rotatable chucks.

the chuck shaft, the radially disposed slots being tapered to a narrowinner end, the tapered slots facilitating improved accuracy inpositioning.

7. The apparatus of claim 1, wherein each of the plurality of indexpositions has an axis, each axis extending through a common center, withadjacent axes enclosing an angle 45 therebetween.

1. Apparatus suitable for carrying a log through a pair of adjustablesaw blades which cut said log longitudinally into lumber, the apparatuscomprising; a carriage with a plurality of wheels adapted to ride alongat least one rail, the carriage being reciprocally movable to conveysaid log through said saw blades; support means connected to thecarriage; a pair of chucks rotatably mounted in the support means andoperable to support said log by engagement substantially centrally ofeach end thereof, one of the chucks being secured to one end of a chuckshaft that can be driven to rotate the chuck and the log; positioningmeans operatively coupled to said one end of the chuck shaft so that thelog can be rotated, while chucked, to an initial selected index positionthat allows the maximum lumber recovery from the log being sawed, thepositioning means including a shaft rotatably mounted in the supportmeans remote from said chuck shaft, and having a free outer end thereof,further including non-extensible chain drive means for coupling saidshafts together, said chain drive means being adapted to be driven torotate the chuck and the log; indexing means secured to the free end ofone of the shafts, the indexing means having a plurality of indexpositions thereon in co-ordinated pairs spaced 90* apart to enablerotation of 90* from the initial selected index position; and lockingmeans that are actuatable to effect holding the positioning means fixedat said initial selected index position and the co-ordinated indexposition.
 2. The apparatus of claim 1, wherein the indexing meanscomprises a circular template having said index positions thereondefined by a series of radially disposed slots on the periphery thereof,and wherein said locking means includes a reciprocally movable pin meansof a shape complemental to said slots, the pin means being engageable inthe slots to positively lock said positioning means in position.
 3. Theapparatus of claim 1, wherein automatically actuatable drive means areoperatively coupled to said chain drive means, the automaticallyactuatable drive means being responsive to a signal provided by a sawyerto effect movement of the chain drive means and simultaneously therewithrotation of the log carried by the two chucks.
 4. The apparatus of claim1, wherein said chain drive means is operatively coupled to a piston andcylinder combination, said combination being actuatable to causereciprocal movement of the piston with such movement simultaneouslyeffecting rotational movement of said chuck shaft and the log beingcarried by the rotatable chucks.
 5. The apparatus of claim 2, whereinsaid support means comprises an enclosure which serves to rotatablymount and house said shafts; the enclosure being rigidly connected tosaid carriage as an integral part thereof, and functioning, in use, as ashield-like deterrent, to sawdust and wood chips which could tend toclog the slots in said indexing template.
 6. The apparatus of claim 5,wherein the indexing template is secured to the end of said shaft remotefrom the chuck shaft, the radially disposed slots being tapered to anarrow inner end, the tapered slots facilitating improved accuracy inpositioning.
 7. The apparatus of claim 1, wherein each of the pluralityof index positions has an axis, each axis extending through a commoncenter, with adjacent axes enclosing an angle 45* therebetween.